A region visited by the Duke and Duchess of Cambridge last year has been
declared off-limits due to fighting between militants and Malaysian troops.

British travellers have been warned to avoid parts of Sabah, on the island of Borneo, following the outbreak of violence.

The Foreign Office is advising against all but essential travel to “an area east of a line joining Sabah’s most northerly point near the town of Kudat to the Indonesian border in the southern part of Sabah, near Tawau”.

The zone, declared a Special Security Area by the Malaysian government, includes parts of the Danum Valley, which was visited last year by the Duke and Duchess of Cambridge, as part of a nine-day Diamond Jubilee tour, and the Sepilok Orang Utan Sanctuary.

The towns of Sandakan, Lahad Datu, Tawau (and their respective airports), Kunak, Semporna, and those islands immediately off the coast, including Sipadan, a popular destination for divers, have also been declared off-limits.

A spokesman for Hayes&Jarvis, which offers tours to Borneo, said only one booking had been affected so far. An alternative itinerary was being offered. “Borneo has been increasing in popularity in the past 18 months and one of its key appeals is the wildlife element," it added. "Fortunately relatively few of our tour bookings are for the affected areas so we hope that the current situation will not deter potential visitors."

The majority of tourists visiting Sabah stay close to Kota Kinabalu, home to the region’s main airport, which does not fall within the restricted area.

Britons throughout the state should exercise caution, the Foreign Office added, comply with the advice of Malaysian authorities, and monitor local media reports.

Its warning comes after the followers of an exiled Filipino sultan landed in Sabah last month, seeking to revive a historical claim to the region. Dozens have been killed in subsequent fighting between the militants and Malaysian troops, while little progress has been made with peace talks.